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Proceedings Paper

New method for the simultaneous measurement of fluorescence and phosphorescence depolarizations
Author(s): Liqun Yang; Daniel McStay; Abhay Sharma; Peter J. Quinn; Alan J. Rogers
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Paper Abstract

A new technique for the simultaneous measurement of fluorescence and phosphorescence depolarization is reported. The technique is based on a newly developed photomultiplier gain suppression technique. The gain suppression characteristics of the circuit were studied by applying a constant level of incident light. To demonstrate this new technique, a solid sample of the triplet probe eosin was excited by a pulsed, frequency doubled Nd:YAG laser; the resulting orthogonally-polarized emissions were collected by two balanced photomultiplier (PMTs). The gains of the PMTs were suppressed for the duration of the fluorescence emission, and subsequently returned to normal, in order to keep the measured fluorescence and phosphorescence signals at the same level. The suppression of the gain was controlled by using a specially designed dual-channel PMT gain suppression circuit. The signals from the PMTs were recorded by two digital oscilloscopes, one set at a fast sweep time in order to measure the transient fluorescence depolarization and the other set at a slow sweep time in order to measure the slow phosphorescence depolarization. The anisotropies can then be deduced from the two sets of recordings.

Paper Details

Date Published: 1 April 1992
PDF: 7 pages
Proc. SPIE 1640, Time-Resolved Laser Spectroscopy in Biochemistry III, (1 April 1992); doi: 10.1117/12.58220
Show Author Affiliations
Liqun Yang, King's College London (United Kingdom)
Daniel McStay, Robert Gordon Institute of Technology (United Kingdom)
Abhay Sharma, Cranfield Institute of Technology (United Kingdom)
Peter J. Quinn, King's College London (United Kingdom)
Alan J. Rogers, King's College London (United Kingdom)

Published in SPIE Proceedings Vol. 1640:
Time-Resolved Laser Spectroscopy in Biochemistry III
Joseph R. Lakowicz, Editor(s)

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